Which of the following actions does not require power

Iknow the answer is a but i don't know why

Much of the general structure and physical properties of the interior of the earth are inferred from: a)deep oil and gas bore holes b)geologic investigations c)analysis of seismic waves d) study of volcanoes

You exhale co2 which is produced during cellular respiration.  co2 combines with the water in your blood's plasma to make up one half of the body's most important buffer pair, carbonic acid.  the more physical activity you engage in, the more co2 your body is producing.  you can see this by putting some of the cabbage indicator in a glass and then blowing bubbles into it through a straw.  can you see a change in the color of the indicator?